Mock within a mock

Mocks returning mocks, returning mocks; unit testing legacy systems sure is a drag.

Foo foo = mock(Foo.class);
Bar bar = mock(Bar.class);
when(foo.getBar()).thenReturn(bar);
when(bar.getName()).thenReturn("deep");

Fortunatly, Mockito has this cool feature called deep stubs, that can ease the pain. The previous code snippet is equivalent to the following:

Foo mock = mock(Foo.class, RETURNS_DEEP_STUBS);
when(mock.getBar().getName(), "deep");

Ain’t that neet?

Of course, this feature should only be used to test legacy code since all your fresh code respects the Law of Demeter. Right? Don’t forget that every time a mock returns a mock a fairy dies.